<template>
  <div class="progress" :style="{
    width: `${percent}%`,
    height: height,
    opacity: show ? 1 : 0,
    'background-color': canSuccess ? color : failedColor
  }"></div>
</template>

<script>
// https://github.com/nuxt/nuxt.js/blob/master/lib/app/components/nuxt-loading.vue
import Vue from 'vue';

export default {
  data: () => ({
    percent: 0,
    show: false,
    canSuccess: true,
    duration: 3000,
    height: '2px',
    color: '#77b6ff',
    failedColor: 'red'
  }),

  methods: {
    start () {
      this.show = true;
      this.canSuccess = true;
      if (this._timer) {
        clearInterval(this._timer);
        this.percent = 0;
      }
      this._cut = 10000 / Math.floor(this.duration);
      this._timer = setInterval(() => {
        this.increase(this._cut * Math.random());
        if (this.percent > 95) {
          this.finish();
        }
      }, 100);
      return this;
    },
    set (num) {
      this.show = true;
      this.canSuccess = true;
      this.percent = Math.floor(num);
      return this;
    },
    get () {
      return Math.floor(this.percent);
    },
    increase (num) {
      this.percent = this.percent + Math.floor(num);
      return this;
    },
    decrease (num) {
      this.percent = this.percent - Math.floor(num);
      return this;
    },
    finish () {
      this.percent = 100;
      this.hide();
      return this;
    },
    pause () {
      clearInterval(this._timer);
      return this;
    },
    hide () {
      clearInterval(this._timer);
      this._timer = null;
      setTimeout(() => {
        this.show = false;
        Vue.nextTick(() => {
          setTimeout(() => {
            this.percent = 0;
          }, 200);
        });
      }, 500);
      return this;
    },
    fail () {
      this.canSuccess = false;
      return this;
    }
  }
};
</script>

<style scoped>
.progress {
  position: fixed;
  top: 0px;
  left: 0px;
  right: 0px;
  height: 2px;
  width: 0%;
  transition: width 0.2s, opacity 0.4s;
  opacity: 1;
  background-color: #efc14e;
  z-index: 999999;
}
</style>
